Pulmonary artery pressure assessed by catheterization and its concordance with transthoracic echocardiographic estimates in patients with pulmonary arterial hypertension: experience of the Colombian Pulmonary Hypertension Network in a real-life study

Abstract

Objective: To evaluate the correlation and concordance of pulmonary artery systolic pressure values measured via right heart catheterization and estimated via transthoracic echocardiography based on data from a multicenter cohort of patients with pulmonary hypertension in Colombia.

Methods: A retrospective study was conducted of patients with pulmonary hypertension classified into Groups 1 or 4 according to the definitions of the ESC/ERS-PH-2022 guidelines. Patients were obtained from the Colombian Pulmonary Hypertension Network (HAPredco) database.

Results: A total of 633 patients were identified and included in this study. Among these patients, 77.7% (n = 492) had complete data from transthoracic echocardiography at diagnosis, 58,3% (n = 369) had complete data from right heart catheterization at the time of diagnosis, and 264 (41.7%) had complete data from both tests at diagnosis, with a difference in days between them of 1 (84). The values of pulmonary artery systolic pressure estimated by transthoracic echocardiography and those obtained by right heart catheterization were significantly correlated (p < 0.001) in the entire population evaluated, as was the correlation assessed for those patients with a gap of ≤ 7 days (p = 0.0001) or ≤ 48 hours (p = 0.041) between the two examinations; however, these findings presented a low Spearman (0.32 for ≤ 7 days and 0.264 for ≤ 48 hours) and Lin´s correlation coefficient (0.32 for ≤ 7 days and 0.21 for ≤ 48 hours).

Conclusion: The pulmonary artery systolic pressure values estimated via transthoracic echocardiography and measured via right heart catheterization were significantly but weakly linearly correlated, with low concordance. These findings suggest interindividual variability between the pulmonary artery systolic pressure values obtained by the two methods, which may have clinical significance in follow-up and decision-making.

Figure 1. Risk assessment defines 1-year mortality in pulmonary arterial hypertension patients.

CF-WHO - World Health Organization functional class; 6MWT - 6-minute walk test; VO₂ - oxygen consumption; VE/VCO₂ - ratio of minute ventilation to carbon dioxide production; BNP - brain natriuretic peptide; NT-proBNP: N-terminal pro-brain natriuretic peptide; RA - right atrium; TAPSE - tricuspid annular plane systolic excursion; PASP - pulmonary arterial pressure; RAP - right atrial pressure; SVO₂ - mixed venous blood oxygen saturation. Risk was defined as 1-year mortality.

Figure 2. Distribution of patients in Group 1 with pulmonary hypertension.

Figure 3. New York Heart Association functional classes.

Distribution of percentages of the study patients in each NYHA functional class. NYHA - New York Heart Association.

Figure 4. Diagram of diagnostic exams.

Diagram of patients with transthoracic echocardiography, right heart catheterization or both. RHC - right heart catheterization; TTE - transthoracic echocardiography.

Figure 5. Scatter plot of pulmonary pressures measured via a pulmonary artery catheter and estimations based on transthoracic echocardiography.

Scatter plot with the regression line for systolic blood pressure (mmHg) measured by right heart catheterization or estimated by transthoracic echocardiography in all patients. The colors represent the groups of patients defined according to the time difference (in days) between the two measurement techniques in each case, right heart catheterization and transthoracic echocardiography, with intervals of less than 2 days, 2–7 days or more than 7 days. The X-axis represents the gold standard of measurement expressed as the pressure measured during pulmonary artery catheterization. The Y axis represents the values estimated via transthoracic echocardiography. Both axes of the graph have the same value scale. The dashed diagonal represents the line of identity and makes it possible to show which values are identical between catheterization and transthoracic echocardiography. The values that are outside the identity line indicate that the agreement is less than 1. Those nonidentical values are distributed in four quadrants. Quadrant a represents the proportion of values that have been overestimated by transthoracic echocardiography. The values in quadrants b and c represent the high and low values, respectively, of both measurement methods that are not necessarily identical. Quadrant d shows pressure values that have been underestimated by transthoracic echocardiography. PAMP - pulmonary artery mean pressure; RHC - right heart catheterization.

Figure 6. Bland–Altman plot for systolic blood pressure (mmHg) measured by right heart catheterization and transthoracic echocardiography.

The red lines correspond to the confidence intervals for the difference vs. the mean of the pulmonary artery pressure variables measured by right heart catheterization and estimated via transthoracic echocardiography.

Figure 7. Heat plot for systolic pulmonary pressure measured by ultrasound and right heart catheterization, classified according to pulmonary vascular resistance.

Heat gradient of transthoracic echocardiography values plotted on the Y axis and right heart catheterization pressures plotted on the X axis, in which the cold colors (blue) represent low values and the warm colors (red) represent high values. VPR - vascular pulmonary resistance.

Figure 8. Heat plot for pulmonary artery systolic pressure estimated by transthoracic echocardiography and measured by right heart catheterization.

The left sidebar corresponds to the dendrogram generated via an average clustering method with a Euclidean distance measure. PASP - pulmonary artery systolic pressure; RHC - right heart catheterization; TTE - transthoracic echocardiography.